The present invention relates to the field of downhole oil, gas, and/or geothermal drilling and more particularly, to apparatus and methods for retrieving downhole data. Smart materials, such as piezoelectric and magnetostrictive materials, may be used as sensors and/or actuators downhole for measuring properties of a downhole formation such as density and porosity as well as increase the rate of penetration. The prior art contains references to drill bits with sensors or other apparatus for data retrieval.
U.S. Pat. No. 6,909,666 to Dubinsky, et al, which is herein incorporated by reference for all that it contains, discloses an acoustic logging apparatus having a drill collar conveyed on a drilling tubular in a borehole within a formation. At least one transmitter is disposed in the drill collar. The transmitter includes at least one magnetostrictive actuator cooperatively coupled by a flexure ring to a piston for converting a magnetostrictive actuator displacement into a related piston displacement for transmitting an acoustic signal in the formation.
U.S. Pat. No. 6,478,090 to Deaton, which is herein incorporated by reference for all that it contains, discloses an apparatus and method of operating devices (such as devices in a wellbore or other types of devices) utilizing actuators having expandable or contractable elements. Such expandable or contrastable elements may include piezoelectric elements, magnetostrictive elements, and heat-expandable elements. Piezoelectric elements are expandable by application of an electrical voltage; magnetostrictive elements are expandable by application of a magnetic field (which may be generated by a solenoid in response to electrical power); and heat-expandable elements are expandable by heat energy (e.g., infrared energy or microwave energy). Expandable elements are abutted to an operator member such that when the expandable element expands, the operator member is moved in a first direction, and when the expandable element contracts, the operator member moves in an opposite direction.
U.S. Pat. No. 6,814,162 to Moran, et al, which is herein incorporated by reference for all that it contains, discloses a drill bit, comprising a bit body, a sensor disposed in the bit body, a single journal removably mounted to the bit body, and a roller cone rotatably mounted to the single journal. The drill bit may also comprise a short-hop telemetry transmission device adapted to transmit data from the sensor to a measurement-while-drilling device located above the drill bit on the tool string.